This invention discloses an unattended lawn mowing system and mechanisms that are solar powered and self actuated, continuously operable, self propelled and random motion mowing devices.
The present day common practice of lawn care uses attended mowing machines that usually include reel or rotary, push-type or self propelled machines powered by gasoline or electrical motors. Such machines are typically stored in a shed or garage until desired operation and are then started and guided over the area to be mowed by a human operator. When the task of mowing the lawn is finished the machine is then stopped and returned to the storage area until further needed to reduce the height of the grass in the area that has been mowed.
Prior art devices not found in common practice today are mowing devices using solar power. U.S. Pat. No. 4,987,729 and 4,942,723 disclose devices similar to the common operator guided (attended) lawn mower, with the exception that the typical gasoline powered motor is replaced by a solar powered electrical motor.
Approaches to unattended mowing devices have been disclosed in U.S. Pat. Nos. 3,570,227 and 3,698,523. The devices disclosed therein have the need for sophisticated electronic boundary hardware and the required attendance of an operator at the beginning, often during, and at the end of relatively short periodic mowing sessions.
Another approach to unattended mowing devices is disclosed in U.S. Pat. No. 5,007,234 but depends on sophisticated equipment to detect the height of the grass to begin and stop operation.
First, the random mowing procedure suggested by the fore mentioned U.S. Pat. No. 3,570,227 is significantly improved upon and simplified by the herein invention eliminating all electronic signal transmitting boundary equipment and all on board signal receiving equipment.
Secondly, the extent of operator attendance is significantly reduced through automatic accommodation of transient obstacles and the elimination of specific mowing sessions, which in turn reduces the time required for start-up, shut-down, and storage procedures.
Periphery sensors on each mowing device respond to an infinite variety of physical obstacles; the locations of which can be of a transient nature. For example, the addition or deletion of a tree or shrub or the simple placement of a child's toy will not hinder the effectiveness of the cutting systems.
Furthermore, the mowing device is equipped with on board circuitry to assure efficient use of the sun's power. This is accomplished by mounting of the photovoltaic cells in a manner to allow optimum sun conjunction with motorized linear or angular actuators. The sun tracking mechanisms and circuitry can be derived from existing technology.
Additionally, the on board circuitry will control the mowing device's motion, on off operation, battery recharging periods, and anti-theft alarm signals.
Simultaneous electronic monitoring of the photovoltaic output and power level of the battery(s) as the device is in motion also improves efficiency of the device through selective avoidance of heavily shaded areas.